Depending on your set of friends, you might want to check out Wrestlemania XIX, but trust me, it's either going to be a big hit, or a big miss.
Also, 4/12/04, Serious Sam: The Next Encounter. 4 player FPS fun for $20. I can never say enough good things about the series, and now, VEHICLES!
And if you want to go FPS style, Timesplitters II, from Free Radical. It's like Goldeneye/Perfect Dark, and fun for four.